The present invention relates generally to detection of a signal having random characteristics, and more specifically to detection of a signal having a random number of pulses, and other potentially random characteristics such as pulse width, spacing between pulses and a random number of pulses within a random number of bursts, within a predetermined time period.
The Federal Communications Commission (FCC) has published requirements for unlicensed wireless devices that operate in the frequency bands 5.250-5.350 GHz or 5.470-5.725 GHz to employ a mechanism to share these bands with radar operations. These requirements are published in FCC 5 GHz Report and Order, RM-10371.
However, the National Telecommunications and Information Administration (NTIA) has distributed an additional requirement to detect a new test signal, referred to as the “Bin-5 Test Signal” which is being recommended to the FCC for inclusion in the test procedure described in RM-10371. Devices unable to detect the Bin-5 Test Signal may not be certified for operation in the 5.250-5.350 GHz or 5.470-5.725 GHz bands in the United States.
Currently, the transmission period for the Bin-5 Test signal is twelve seconds. The Bin-5 test signal will have a total of 8 to 20 pulse bursts within the twelve second period, with the number of bursts being randomly chosen. Each burst will consist of one to three pulses, with the number of pulses being randomly chosen. Each pulse within a burst will have a linear FM of 5-20 MHz (each pulse within the burst will have the same amount of chirp). Each pulse burst within the twelve second time period may have different chip widths. Each pulse in a burst will have the same randomly chosen length between 50 to 100 microseconds with a minimum resolution of 5 microseconds. If more than one pulse in present in a burst, each space between the pulses will be a randomly chosen time between 1000 and 2000 microseconds (or 1 to 2 milliseconds) with a 1 microsecond minimum resolution. Each burst will be placed at a random starting location.
An example Bin-5 Test Signal is illustrated in FIG. 1. Each burst, 1, 2, 3 . . . N occurs within a corresponding Burst Interval. As illustrated Burst 1 has two pulses, Burst 2 has one pulse, Burst 3 has three pulses, Burst 4 has two pulses . . . and Burst N has one pulse. The pulse widths and spacing between pulses is random.
The Bin-5 Test Signal will not be detected by prior art systems. Thus, there is a need for a method and apparatus that can accurately detect the Bin-5 Test Signal, or test signals having random characteristics similar to the Bin-5 Test Signal. Detecting the Bin-5 Test Signal requires distinguishing it from wireless network traffic. Without being able to distinguish the test signal from network traffic, false detection from network traffic may occur frequently, rendering a detection solution impractical.